Our paper on exploring the limits of phonon interferometry as rotation sensors has been published in SciPost Physics!

In this work, we cool down rubidium atoms to close to absolute zero to form a Bose Einstein Condensate. We form this condensate into a ring, then create sound waves travelling around the circumference of the ring. These sound waves (or phonons) create a standing wave in the density of the condensate, with high- and low-density points around the ring which act as markers. Due to the superfluid nature of the condensate, these markers stay in the same location of the ring and don’t rotate, even if the lab frame of reference is rotating (e.g. due to Earth’s rotation). This means that these markers act as an absolute frame of reference - like the north-seeking pole on a compass and so could potentially be used for navigation in situations where satellite navigation is not available e.g. under water.

The longer these markers are visible, the more accurate the rotation measurement will be. We find that they do not persist for as long as has been predicted, and we propose a mechanism of why this is. We model the system and achieve very similar results to the experimental realisation.

You can find the full text here!